Control system for electric elevators



Jan. 23, 1934. E. w. SEEGER 1,944,471

CONTROL SYSTEM FOR ELECTRIC ELEVATORS Filed June 15, 1930 2 Sheets-Sheet 1 FLOOR 5 Jan. 23, 1934.

E. w. SEEGER 1,944,471

CONTROL SYSTEM FOR ELECTRIC ELEVATORS Filed June 13, 1930 2 Sheets-Sheet 2 O/WMMA" 50mm 9%.

Patented Jan. 23, 1934 UNEEED S'EY'A'EES CONTROL SYSTEM FOR ELECTRIC ELEVATORS Edwin W. Seeger, Nauwatosa, Wis, assignor to Cutler-Hammer, 1110., Milwaukee, Wis, a corporation of Delaware Application June 13, 1936. Serial No. 460,951

7 Claims.

This invention relates to control systems for electric elevators.

While not limited thereto the invention is particularly applicable to elevator systems of the 1push button controlled type wherein provision is made for effecting automatic stopping of the elevator car at a selected landing.

The invention has among its objects to provide an elevator controller having improved and simplified control means for effecting accurate stopping of the elevator car at a selected landing.

Another object is to provide an automatic elevator system having improved means associated therewith for automatically stopping the elevator car at a selected landing and for insuring against restarting thereof except upon closure of all of the landing doors.

Another object is to provide a system of the aforesaid character wherein automatic stopping of the elevator car at a preselected landing and prevention of restarting thereof except upon closure of all of the landing doors is effected through the medium of control switches associated with the landing door locks.

Another object is to provide an elevator system of the aforesaid character which provides for slowdown of the elevator car during approach thereof to a selected landing.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate a system embodying the invention, it being understood that the system shown is susceptible of modification without departing from the spirit and scope of w; the appended claims.

In the drawings,

Figure 1 is a diagrammatic view of the driving motor of the elevator and the elements employed for controlling the same.

2 is a diagrammatic View illustrating the control means for the elements shown in Fig. 1.

Fig. 3 is a schematic view of an elevator car having a mechanism associated therewith for controlling certain of the switches shown in Fig. 2, and

Figs. 4; and 5 are sectional views of one of the control switches shown in Fig. 3.

Referring to Fig. 1 of the drawings, the same illustrates a reversible driving motor M having an armature A, a series field winding F, a shunt field winding F steps R to R of series starting resistance, a step oi resistance R for limiting current to the shunt field winding and a further step R of dynamic braking resistance to be connected .in a closed loop including the armature A for slowdown. An electromagnetic brake B is associated with the motor, said brake being provided with windings B and B lwo sets of electromagnetically operated reversing switches 9-10 and 11-12 control the armature circuit of the motor in the usual manner, whereas a conventional form of dash pot retarded electroresponsive accelerator 13 provides for progressive exclusion of the steps of starting resistance R to R the series field winding F being also excluded on the last accelerating step and the motor being thereafter adapted to act under shunt field energization only. For purposes hereinafter set forth each of the reversing switches 9 and 11 is provided with normally open auxiliary contacts I) and c and a normally closed auxiliary contact d as shown in Fig. 2.

The shunt field winding F is permanently connected across the motor supply lines L L through resistance R and said resistance is adapted to be excludedby an electromagnetically operated switch 14 which also serves to connect the coil B of brake B across said supply lines. An electroresponsive switch 15 serves to control the continuity of the aforementioned dynamic braking loop which includes resistor R and as hereinafter set forth said switch is provided with normally open auxiliary contacts 15 for controlling the energizing circuit of accelerator 13.

Referring now to Fig. 2, the same illustrates the motor M and the aforedescriced control elements 9 to 15, inclusive, and since the circuit connections for said elements are clearly shown in Fig. 1 the same have been omitted in Fig. 2.

The two sets of reversing switches 9-l0 and 11-12 and also the field switch 14 are under the control of a plurality of electromagnetic relays including a door switch relay 16, an up relay 1'? and a down relay 18. The door switch relay is provided with normally open contacts 16 and 16 while the up relay 1? and down relay 13 are each provided with normally open auxiliary contacts I) normally closed auxiliary contacts 0. Relay it is controlled through the medium of a plurality or" door switches which will be hereinafter more fully described, and as is apparent from Fig. 2 with relay 16 closed the up relay 17 in responding connects the operating windings of reversing switches 9-19 and field switch .14 across lines Li -L for operation of the motor in its up direction, while the down relay 18 in responding connects the operating windings of reversing switches 11-12 and field switch 14 across lines L -L for operation of the motor in its down direction. Also as is apparent from Fig. 2 upon response of reversing switch 9 relay 17 is shunted by auxiliary contacts 9 and upon response of reversing switch 11 relay 18 is shunted by auxiliary contacts 11 Thus either set of reversing switches in responding is maintained energized until the door switch relay 16 is opened.

The control means for relays 17 and 18 includes an automatic floor selector indicated at 19, electromagnetic floor relays 20, 21 and 22, said relays being normally open and one being provided for each landing, the two groups of push button switches 222324 and 25--26-2'7, the switches of the former group being located in the elevator car and corresponding in number to the number of landings and the switches of the latter group being located individually at the several landings.

Floor selector 19 includes a rotatable drum 30 which is driven at a reduced speed by the driving motor or otherwise operated at a. speed proportional to that of the elevator car. Said drum is provided with contact segments 31 and 32 which cooperate with stationary contacts 33 to 37, inclusive, to commutate the control circuits for relays 17 and 18 in a manner which will be hereinafter described.

The push buttons 22 to 27, inclusive, are similar to one another in construction and each includes a pair of normally closed up contacts a, and a pair of normally open down contacts b. Energization of the circuit to each push button except the first is dependent upon closure of the normally closed contacts a of all of the preceding push buttons, precedence being given to the upper as opposed to the lower landing buttons and to the car buttons as opposed to the landing buttons. Hence it follows that operation of any push button serves to render ineffective all push buttons therebeyond during enactment of the function of the controller selected by the push button so actuated. Thus if two or more push buttons are actuated simultaneously the push button nearest the energy supply prevails and interference from this source is obviated. The common supply circuit to all or the push buttons 22 to 27, inclusive, passes through a normally closed stop push button 38 which is located within the elevator car, and as hereinafter set forth said stop push button also controls the energizing circuit of the door switch relay 16.

As hereinbefore stated the door switch relay 16 is controlled through the medium of a plurality of door switches. Said door switches are indicated by reference characters DS DS and D8 in Fig. 2 and each of the same is associated with one of the landing doors and is of the construction illustrated in Figs. 4 and 5.

As shown in Figs. 4 and 5 each of the door switches includes a pair of stationary contacts 40-40 and a cooperating bridging contact 41. Contacts 40-40 are mounted within an enclosing casing 42 which is designed for mounting upon the jam of the landing door and bridging contact 41 is mounted upon a latch 43 which cooperates with a bolt 44 fixed to the landing door D. Contacts 40-40 are insulated from casing 42 and each of the same is provided with a terminal device 45. The latch 43 is rotatably mounted upon a pin 46 fixed to casing 42, and said latch is provided with a locking projection 47 which is movable into an opening 48 in bolt 44 to lock the landing door D in closed position. As shown in Fig. 4, when latch 43 occupies its locking position bridging contact 41 engages contacts 40-40 and upon movement of said latch to the released position indicated in Fig. 5 the former contact disengages the latter.

Latch 43 is provided with a weighted arm 49 which extends through an opening in casing 42 and has a roller 50 mounted upon the free end thereof. The arm 49 biases latch 43 towards its locking position, and as hereinafter set forth a cam 51 (Fig. 3) is mounted upon the elevator car and is adapted to engage the roller 50 to move latch 43 to its released position. A lever 4:3 is rotatably mounted upon a pin fixed to casing 42, and as shown in Fig. 4 when the door is in its closed position the inner end of bolt 44 engages said lever to hold the same out of engagement with latch 43. However, upon opening of the door the lever 4.3 drops by gravity to the position shown in Fig. 5 to hold the latch 43 in its unlocking position.

As shown in Fig. 3 cam 51 is secured to the elevator car E through the medium of a pair of toggle joints 52 and a lever 53, and a spring 54 acts upon said toggles to normally hold said cam in the projected position shown in full lines in the drawings. Cam 51 is movable to a retracted position illustrated by dotted lines upon energization of a motor M Motor M is mounted upon the top of the elevator car and when energized the same acts through the medium of an arm 56 and a cable connection 5'7 to move the toggle joints upwardly to thereby effect retraction of said cam. As shown in Fig. 2 motor M is provided with an armature A and a series field winding F, and as hereinafter set forth said motor is controlled through the medium of the normally open contacts 12 associated with relays 1'7 and 18.

In addition to the aforedescribed control means the system shown in Fig. 2 is provided with various conventional protective devices including up and down overtravel switches 60 and 61 and an overspeed governor switch 62.

The function and operation of the aforedescribed controller together with the circuit connections thereof will now be more fully described.

When the elevator car is located at the second landing selector l9 occupies the position shown in Fig. 2. Assume now that a person entering the car desires to descend to the first landing. The push button 24 is thereupon depressed to establish an energizing circuit for down relay 18 extending from line L through stop push button 38, through auxiliary contacts 11 and 9 of reversing switches 9 and 11, through the down contacts 24 of push button 24, through the operating winding 20 of floor relay 20 to contact 33, through contact segment 31 to contact 37, through the operating winding 18 of the down relay, through auxiliary contacts 17 of the up relay and thence through the protective switches 60, 61 and 62 to line L Upon response of down relay 18 the cam 0perating motor M is connected across lines L -L" by the contacts 18 of said relay and said motor then operates to move cam 51 to its retracted position. Assuming that the door at the second landing is closed door switch DS" closes upon retraction of cam 51 and upon closure of said door switch the door switch relay 16 is energized by a circuit extending from line L through stop push button 38 through the operating winding 16 of said relay through the door switches DS DS and DS and through the protective devices 60, 61 and 62 to line L.

As hereinbefore set forth reversing switches 11-12 and field switch 14 respond upon closure of relay 18 and door switch relay 16, and said switches in responding are maintained energized until said door switch relay is opened. Upon response of reversing switch 11 the supply circuit from line L to push button 24 is interrupted by auxiliary contacts 11 of said reversing switch. However, fioor relay 20 and down relay 18 are now maintained energized by a circuit extending from line L through stop .push button 38, through the door switch relay contacts 16*, through relay 20 and its operating winding 20, through contacts 33, 31 and 3'7 of fioor selector 19 and through the operating winding 18 to line L Also upon response of reversing switch 11 an energizing circuit for the dynamic braking switch 15 is established extending from line L through contacts 18 of the down relay, through auxiliary contacts 11 of reversing switch 11 through the operating winding 15 of said dynamic braking switch and through the protective devices 60, 61 and 62 to line L Upon response of dynamic braking switch 15 an energizing circuit for accelerator 13 is established extending from line L through auxiliary contacts 15 of said dynamic braking switch to and through the operating winding 13 of said accelerator to line L As is apparent from Fig. 1, the above described operations of the controller provide for starting and acceleration of motor M in its down direction. Closure of reversing switches 11 and 12 connects the motor armature A and series field winding F across lines L -L through resistances R to R and response of field switch 14 excludes resistance R from the shunt field circuit. Response of dynamic braking switch 15 excludes resistance R and response of accelerator 13 progressively excludes resistances R to R the series field winding F being also excluded on the last accelerating step. Brake coil 13 is energized to release brake B upon establishment of the armature circuit and on the last accelerating step said coil is excluded from the armature circuit. However, brake B is then held released by coil B which is connected across line L L by field switch 14.

During lowering operations of the elevator car drum 30 of the floor selector 19 rotates in a counterclockwise direction and prior to arrival of the elevator car at the first landing contact segment 31 disengages contact 33 to interrupt the aforedescribed maintaining circuit for down relay 18. Relay 18 then opens and interrupts the aforedescribed energizing circuit for the dynamic braking switch 15 and opening of said dynamic braking switch interrupts the aforedescribed energizing circuit for the operating winding 13 of accelerator 13. Accelerator 13 then returns to normal position to effect slowdown of the motor M by inserting resistances R to R in the armature circuit thereof. Return of relay 18 to normal position also interrupts the aforedescribed energizing circuit for motor M and upon deenergization of said motor cam 51 moves to its projected position. During final movement of the elevator car into a position opposite the first landing cam 51 opens door switch DS and said door switch in opening interrupts the energizing circuit for the door switch relay 16. Opening of relay 16 interrupts the aforedescribed maintaining circuit for reversing switches 11 and 12 and field switch 14 and motor M is then brought to rest under the action of the dynamic braking connection established by switch 15 and under the action of brake B.

When the elevator car is located at the third landing the floor selector 19 occupies a position wherein contacts 33, 34 and 37 are in engagement with contact segment 31. With the floor selector in this position it is apparent that the controller will operate in the manner hereinbefore de-- scribed upon depression of a push button corresponding to the first landing. However, upon depression of a push button corresponding to the second landing the down relay is energized by a circuit extending from line L through the stop push button 38, through auxilliary contacts 11 and 9 associated with reversing switches 11 and 9, through the depressed push button corresponding to the second landing, through operating winding 21 of floor relay 21, through contacts 34, 31 and 37 of the floor selector and thence through the operating winding 18 of the down relay to line L as already traced. Floor relay 21 in responding establishes a maintaining circuit for itself and down relay 18 extending from line L through contacts 16 of the door switch relay, through relay 21 and its operating winding 21 and thence through the floor selector 19 and the operating winding 18 to line L as already traced. The motor then operates in its down direction as hereinbefore described, and during approach of the elevator car to the second landing contact segment 31 disengages contact 34 to effect deenergization of down relay 18. Opening of relay 18 causes slowdown of the motor and projeotion of cam 51 as hereinbefore set forth. During final movement of the elevator car into a position opposite the second landing door switch BS is opened by cam 51 and relay 16 then returns to normal position to stop motor M The up relay 1'? functions in substantially the same manner for hoisting operations as does the down relay 18 during lowering operations. Relay 17 in responding energizes the cam operating motor M through the medium of its auxiliary contacts 1'7 and the door switch corresponding to the landing at which the elevator car is located is then adapted to close to effect emergization of the door switch relay 16. Closure of the up relay 1'? and door switch relay 16 provides for energization of reversing switches 9 and 10 and field switch 14 and as hereinbefore set forth said switches are then maintained in closed position and motor M is adapted to operate in its up direction. Upon closure of reversing switch 9 the dynamic braking switch 15 is energized by a circuit extending through auxiliary contacts 1'7 associated with the up relay 17 and auxiliary contacts 9 associated with reversing switch 9 and the dynamic braking switch 5 in responding establishes an energizing circuit for accelerator 13 as hereinbefore set forth.

During hoisting operations relay 17 is deenergized during approach of the elevator car to a selected landing and upon opening of said relay the motor is slowed down due to deenergization of the accelerator 13 and dynamic braking switch 15. Also upon opening of relay 1? the cam operating motor M is deenergized to permit movement of cam 51 into its projected position and during final movement of the elevator car into a position opposite the selected landing said cam opens the door switch DS at such landing to deenergize the door switch relay 16 and thereby stop the motor M.

When the elevator car is located at the second landing the selector device 19 occupies the position shown in the drawing and upon depression of the push button corresponding to the third landing the up relay 17 is energized by a circuit extending from line L through stop push button 88, through auxiliary contacts 11 and 9 lie associated with reversing switches 9 and 11, through the depressed push button corresponding to the third landing, through the operating winding 22 of relay 22, through contacts 35, 32 and 36 of floor selector 19, through the operating winding 1'7 of the up relay, through auxiliary contacts 18 of the down relay, and thence through the protective devices 60, 61 and 62 to line L Upon response of relay 22 the same establishes a maintaining circuit for itself and relay 17 through the medium of the contacts 16* of the door switch relay 16. During upward movement of the elevator car the drum 30 of floor selector 19 rotates in a clockwise direction and during approach of the elevator car to the third landing contact segment 31 disengages contact 35 to interrupt the aforedescribed maintaining circuit for up relay 17.

When the elevator car is located at the first landing contact 34 is in engagement with contact segment 32 and the up relay can then be energized as hereinbefore set forth by a push button corresponding to the third landing or by a push button corresponding to the second landing. With the elevator car at the first landing ing winding 1'? of the up relay to line L as already traced. Upon response of the floor relay 21 the same establishes a maintaining circuit for itself and relay 17 through the medium of contacts 16 of down switch relay 16. During approach of the elevator car to the second landing contact segment 32 disengages contact 34 to interrupt the aforedescribed maintaining circuit for up relay 1'7.

Depression of the stop push button 38 interrupts the energizing circuit for the door switch relay l6 and as is apparent from the foregoing, opening of said relay interrupts the maintaining circuit for the reversing switches 9-10 or 11-12 as the case may be, to effect immediate stopping of motor M. The motor M can then be restarted by depressing a push button corresponding to any one of the landings.

While the system disclosed provides for but three landings, it is apparent that by increasing the number of push buttons and floor relays and by adding contacts to the floor selector the system can be modified to serve an increased number of landings. Also it is apparent that the driving motor may be of any desired type.

What I claim as new and desire to secure by Letters Patent is:

1. In a control system for elevators provided with a plurality of landing doors, the combination with a car and a hoisting motor therefor, of a locking device for each of the landing doors, a switch associated with each of said devices, each of said devices being adapted to open its associated switch upon unlocking of its associated door, and to close the same upon locking of its associated door, means acting upon closure of all of said switches to effect starting of said motor and acting upon opening of any one of said switches to effect stopping of said motor, and means for controlling said locking devices to effect starting of said motor when the elevator car is at any one of its landings and to effect automatic stopping of said motor upon movement of the elevator car into a position opposite a selected landing.

2. In a control system for elevators provided with a plurality of landing doors, the combination with a car and a hoisting motor therefor, of a locking device for each of the landing doors, a switch associated with each of said devices, each of said devices being adapted to open its associated switch upon unlocking of its associated door and to close the same upon locking of its associated door, means under the control of said switches for starting said motor upon closure of all of said switches and for stopping said motor upon opening of any one of said switches, and means for selectively controlling the direction of operation of said motor and for controlling said locking devices to effect starting of said motor when the elevator car is at any one of its 1andings, and to eifect automatic stopping of said motor upon movement of the elevator car into a position opposite a selected landing.

3. In a control system for elevators provided with a plurality of landing doors, the combination with a car and a hoisting motor therefor, of a locking device for each of the landing doors, a switch associated with each of said devices, each of said devices being adapted to open its associated switch upon unlocking of its associated door and to close the same upon locking of its associated door, means under the control of said switches for starting said motor upon closure of all of said switches and for stopping said motor upon opening of any one of said switches, a retiring cam mounted upon the elevator car for effecting operation of said locking devices, and means for controlling said cam to effect starting of said motor when the elevator car is at any one of its landings, and to effect automatic stopping of said motor upon movement of the elevator car into a position opposite a selected landing.

4. In a control system for elevators provided with a plurality of landing doors, the combination with a hoisting motor, of a lock associated with each of the landing doors, means for controlling starting and stopping of said motor, said means including a switch associated with each of the landing door locks, each of said switches being adapted to stop said motor upon unlocking of its associated lock and to prevent restarting of said motor except upon locking of its asociated lock, and means mounted upon the elevator car and adapted to act automatically during movement of the elevator car into position opposite a selected landing to unlock the look at such landing.

5. In a control system for elevators having a plurality of landing doors, the combination with an elevator car, of a driving motor therefor, a

plurality of push button switches located within the car, and at the respective landings, means controlled by said push button switches for starting said motor and for eilecting slowdown thereof during approach of the lected landing, and means for stopping said motor upon movement of the elevator car into a position opposite a selected landing, said latter means including a lock associated with each of the landing doors, means acting durin fin l 3;.

movement of the elevator car into a position opposite a selected landing to unlock the lock associated with the door at such landing, and a switch associated with each of said locks, each of said switches being adapted to act upon unlocking elevator car to a se- 7 of its associated lock to effect stopping of said motor.

6. In a push button elevator system, the combination with a reversible motor for driving the elevator car, of a plurality of push button switches operable selectively to initiate operation of the motor, means comprising a selector switch cooperating with said push button switches to predetermine the direction of operation of the motor and to effect slowdown of the motor during approach of the elevator car to a selected landing, and means for stopping the elevator car at a selected landing, said means comprising a door lock located at each landing, a switch associated with each door lock, each of said switches being adapted upon unlocking of its associated lock to stop said motor, and a cam mounted upon the elevator car and rendered operative upon slowdown of the motor to unlock the look at the selected landing during final movement of the elevator car into a position opposite such landing.

7. In a control system for elevators provided with a plurality of landing doors, the combination with an elevator car and a driving motor therefor, of means for selectively controlling operation of said motor to effect travel of said car to a preselected landing and to effect slowdown of the motor during approach of the elevator car to the selected landing, a latch associated with each of the landing doors, means rendered operative upon slowdown of the motor to effect release of the latch associated with the door at the selected landing, and a switch associated with each of said latches, each of said switches being adapted to act upon release of its associated latch to stop said motor.

EDWIN W. SEEGER. 

